Improvement in sewing-machines



UNITED STATES JONATHAN RAMSAY, JR., OF MIDDLETOWN, CONNECTICUT.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 117,459, dated July 25,1871.

To all whom it may concern:

Be it known that l, JONATHAN RAMsAY, Jr., of Middletown, in the countyof Middlesex and State of Connecticut, have invented a new and usefulImprovement in Sewing-Machines; and I do hereby declare the following tobe a full, clear, and exact description thereof, which will enable thoseskilled in the art to make and use the same, referencebeing had to theaccompanying drawing forming part of this specification, in which.drawing- Figure l represents an inverted plan of this invention. Fig. 2is a transverse vertical section of the same.

Similar letters indicate corresponding parts.

This invention relates particularly to an improvement in mechanism forproducing the fourmotion feed 5 and it consists in the arrangement oftwo independent eccentrics or cams, in combination with two rock-shafts,each carrying two arms, one of the eccentrics and rockshafts serving toimpart to the feedbar the backward-andforward motion, while the othereccentric and rock-shaft imparts to the feed-bar. the risingand-fallin gmotion in such a manner that, by ad justing the arms or levers on therock-shafts, the backward#and-forward motion of the feedbar can bereadily brought in the proper relation to the rising-and-i'allingmotion. One of the rock-shafts is made in the form of a tube or sleevefitting on the other rock-shaft, so as to simplify the construction ofthe mechanism and to dispense with eXtra bearings for each of therock-shafts. l

In the drawing, A designates the cloth-plate of a sewingmachine, fromthe under surface of which extend two lugs, a a, which form the bearingsfor the driving-shaft B. On this shaft is mounted an eccentric, b, whichconnects, by a strap, o, with a lever, eZ, that is secured, by means ofa set-screw, e, on a rock-shaft, j'. This rockshaft has its bearings inlugs g y, cast with or otherwise firmly secured to the cloth-plate A,and from said rock-shaft extends a rod, h, which connects, by means of asleeve, fZ, and rod 7c, with a lever, Z. The sleeve?) embraces a nut, m,

which screws on the rod h, (see Fig. 2,) so that by turning said nut thesleeve can be` brought closer to or further from the center of therockshaft j', and by these means the throw of the lever Z is regulated.The lever Z has its fulcrum on a stud, n, which is secured in a lug, o,pro- `iecting from the bottom surface of the clothplate, and the innerend of said lever is bifurcated and made to straddle a pin, p,projecting from the feedbar D. One end of this feed-bar is provided witha slot that catches over a pin, q, secured in a lug, r, which projectsfrom the bottom surface of the cloth-plate, while the opposite end ofsaid feed-bar is provided with a shoulder, s, that rests upon a lever,t, being depressed thereon by a spring, a. By the oscillating motion ofthe lever Z, therefore, a reciprocating motion is imparted to thefeed-bar; and the length of this reciprocating motion can be regulatedby the nut m and sleeve fZ. The lever t, which supports one end of thefeed-bar, eX- tends from a tube, o, which embraces the rockshaft j', andfrom which extends a second lever, w, which bears against a cam oreccentric, a', mounted on the main shaft B. The feed-bar spring u servesto keep the lever fw in contact with the ca-m ax, and, as the main shaftrevolves, this cam imparts to the tube o an oscillating motion entirelyindependent of that ofthe rockshaft j', and by this oscillating motion arisingand-falling motion is imparted to the feed-bar.

In order to produce the proper feed-motion, the reciprocating motion ofthe feed-bar must be brought in such relation to its rising-and-fallingy motion that the feed-dog is raised above the surface of thecloth-plate before the forward motion of the feed-bar begins, and thatthe feed-dog is depressed below the surface of the cloth-plate beforethe retrograde motion of the feed-bar begms.

By my mechanism I am enabled to bring the several motions of thefeed-bar in the proper relation toward each other, without loss of time,simply by changingv the position of the lever d or that ofthe lever w,-and by means of the nut m and sleeve l) the length of the stitches canbe regulated with the greatest nicety.

It will be noticed that the tube@ forms a rockshaft which has itsbearings on the rock-shaft j'.

Vhat l claim as new, and desire to secure by Letters Patent, isy Thearrangement of the cam Z), strap c, lever eZ, rock-shaft f, rod h,adjustable link k, oscillating lever Z, sleeve t, levers t w, cam w,spring u, and the feed-bar and driving-shaft, as herein shown anddescribed, for the purpose 'speciiied J ONA. RAMSAY, JR. Witnesses:

D. C. SAGE, E. RocKwELL.

